[llvm-dev] LLVM Orc Weekly #28 -- ORC Runtime Prototype update

Lang Hames via llvm-dev
Mon, 18 Jan 2021 21:45:05 -0000

Hi Stefan,

% ./bin/llvm-jitlink -oop-executor inits.o
> JIT session error: Symbols not found: [
> __ZTIN4llvm6detail14format_adapterE ]


I've been testing with a debug build:

% xcrun cmake -GNinja -DCMAKE_BUILD_TYPE=Debug
-DLLVM_ENABLE_PROJECTS="llvm;clang;compiler-rt" ../llvm

Matching this build might fix the issue, though building with my config (if
it works) is only a short-term fix. The error that you're seeing implies
that the runtime is dependending on a symbol from libSupport that is not
being linked in to the target (llvm-jitlink-executor). I'll aim to break
these dependencies on libSupport in the future. Mostly that means either
removing the dependence on llvm::Error / llvm::Expected (e.g. by creating
stripped down versions for the orc runtime), or making those types
header-only.

-- Lang.





On Tue, Jan 19, 2021 at 12:50 AM Stefan Gränitz <stefan.graenitz at
gmail.com>
wrote:

> Wow, thanks for the update. One more ORC milestone in a short period of
> time!
>
> On macOS I built the C++ example like this:
>
> % cmake -GNinja -DLLVM_TARGETS_TO_BUILD=host
> -DLLVM_ENABLE_PROJECTS="clang;compiler-rt" ../llvm
> % ninja llvm-jitlink llvm-jitlink-executor
> lib/clang/12.0.0/lib/darwin/libclang_rt.orc_osx.a
> % clang++ -c -o inits.o inits.cpp
>
> The in-process version works perfectly, but with the out-of-process flag
> the examples fails:
>
> % ./bin/llvm-jitlink inits.o
> Foo::Foo()
> Foo::foo()
> Foo::~Foo()
> % ./bin/llvm-jitlink -oop-executor inits.o
> JIT session error: Symbols not found: [
> __ZTIN4llvm6detail14format_adapterE ]
>
> Any idea what could go wrong here? Otherwise I can try to debug it later
> this week. (Full error below.)
>
> Best
> Stefan
>
> --
>
> JIT session error: Symbols not found: [
> __ZTIN4llvm6detail14format_adapterE ]
>
/Users/staefsn/Develop/LLVM/monorepo/llvm-orc-runtime/build/bin/llvm-jitlink:
> Failed to materialize symbols: { (Main, {
> ___orc_rt_macho_symbol_lookup_remote,
>
__ZN4llvm3orc6shared21WrapperFunctionResult22destroyWithArrayDeleteE39LLVMOrcSharedCWrapperFunctionResultDatay,
>
__ZNSt3__113__vector_baseIN4llvm3orc6shared25MachOJITDylibInitializersENS_9allocatorIS4_EEED2Ev,
>
__ZNK4llvm8ExpectedINS_3orc6shared21WrapperFunctionResultEE22fatalUncheckedExpectedEv,
>
__ZN4llvm3orc6shared21toWrapperFunctionBlobIJNSt3__112basic_stringIcNS3_11char_traitsIcEENS3_9allocatorIcEEEEEEENS1_21WrapperFunctionResultEDpRKT_,
> __ZN4llvm3orc6shared20VectorRawByteChannelD1Ev,
>
__ZN4llvm3orc6shared21SequenceSerializationINS1_20VectorRawByteChannelEJNSt3__16vectorINS1_25MachOJITDylibInitializers13SectionExtentENS4_9allocatorIS7_EEEESA_SA_EE11deserializeISA_JSA_SA_EEENS_5ErrorERS3_RT_DpRT0_,
>
__ZNSt3__16vectorIN4llvm3orc6shared25MachOJITDylibInitializers13SectionExtentENS_9allocatorIS5_EEE8__appendEm,
>
__ZN4llvm3orc6shared21toWrapperFunctionBlobIJyNSt3__112basic_stringIcNS3_11char_traitsIcEENS3_9allocatorIcEEEEEEENS1_21WrapperFunctionResultEDpRKT_,
> __ZN4llvm29VerifyEnableABIBreakingChecksE,
> __ZN4llvm15format_providerImvE6formatERKmRNS_11raw_ostreamENS_9StringRefE,
>
__ZNSt3__114__split_bufferIN4llvm3orc6shared25MachOJITDylibInitializersERNS_9allocatorIS4_EEED2Ev,
> __ZTVN4llvm6detail23provider_format_adapterIRmEE,
>
__ZN4llvm3orc6shared21SequenceSerializationINS1_20VectorRawByteChannelEJyNSt3__112basic_stringIcNS4_11char_traitsIcEENS4_9allocatorIcEEEEEE9serializeIRKyJRKSA_EEENS_5ErrorERS3_OT_DpOT0_,
> __ZTVN4llvm6detail23provider_format_adapterImEE,
>
__ZN4llvm6detail23provider_format_adapterImE6formatERNS_11raw_ostreamENS_9StringRefE,
> __ZN4llvm6detail23provider_format_adapterIRmED1Ev,
> ___orc_rt_macho_get_deinitializers_tag,
> __ZN4llvm6detail23provider_format_adapterIRmED0Ev,
> __ZTVN4llvm3orc6shared14RawByteChannelE,
> __ZN6orc_rt12jit_dispatchEPKvN4llvm8ArrayRefIhEE,
> __ZN4llvm3orc6shared20VectorRawByteChannelD0Ev,
> __ZTVN4llvm3orc6shared20VectorRawByteChannelE,
> __ZN4llvm8cantFailENS_5ErrorEPKc,
> __ZN4llvm6detail23provider_format_adapterImED1Ev,
> __ZTVN4llvm6detail23provider_format_adapterIRjEE,
> __ZN4llvm6detail23provider_format_adapterImED0Ev,
> __ZN4llvm15format_providerIjvE6formatERKjRNS_11raw_ostreamENS_9StringRefE,
> __ZTSN4llvm3orc6shared14RawByteChannelE,
>
__ZN4llvm6detail23provider_format_adapterIRjE6formatERNS_11raw_ostreamENS_9StringRefE,
> __ZN4llvm6detail23provider_format_adapterIRjED0Ev,
>
__ZN4llvm3orc6shared19SerializationTraitsINS1_20VectorRawByteChannelENSt3__16vectorINS1_25MachOJITDylibInitializersENS4_9allocatorIS6_EEEES9_vE11deserializeERS3_RS9_,
> __ZTIN4llvm6detail23provider_format_adapterImEE,
>
__ZN4llvm6detail15HelperFunctions15consumeHexStyleERNS_9StringRefERNS_13HexPrintStyleE,
> __ZTIN4llvm6detail23provider_format_adapterIRmEE,
> ___orc_rt_macho_get_initializers_tag,
> __ZTSN4llvm6detail23provider_format_adapterImEE,
> __ZN4llvm3orc6shared20VectorRawByteChannel4sendEv,
>
__ZN4llvm6detail23provider_format_adapterIRmE6formatERNS_11raw_ostreamENS_9StringRefE,
> ___orc_rt_macho_symbol_lookup_tag,
> __ZTSN4llvm6detail23provider_format_adapterIRmEE,
> __ZN4llvm3orc6shared20VectorRawByteChannel11appendBytesEPKcj,
> __ZTSN4llvm6detail23provider_format_adapterIRjEE,
> __ZN4llvm3orc6shared20VectorRawByteChannel9readBytesEPcj,
> __ZTSN4llvm3orc6shared20VectorRawByteChannelE,
> __ZN4llvm6detail23provider_format_adapterIRjED1Ev,
> __ZN4llvm3orc6shared14RawByteChannelD1Ev,
>
__ZN4llvm3orc6shared23fromWrapperFunctionBlobIJNSt3__16vectorINS1_25MachOJITDylibInitializersENS3_9allocatorIS5_EEEEEEENS_5ErrorENS_8ArrayRefIhEEDpRT_,
> __ZN4llvm3orc6shared14RawByteChannelD0Ev,
>
__ZN4llvm3orc6shared21SequenceSerializationINS1_20VectorRawByteChannelEJyyNSt3__16vectorINS1_25MachOJITDylibInitializers13SectionExtentENS4_9allocatorIS7_EEEESA_SA_EE11deserializeIyJySA_SA_SA_EEENS_5ErrorERS3_RT_DpRT0_,
>
__ZNSt3__16vectorIN4llvm3orc6shared25MachOJITDylibInitializersENS_9allocatorIS4_EEE8__appendEm,
>
__ZN4llvm3orc6shared21SequenceSerializationINS1_20VectorRawByteChannelEJyyEE11deserializeIyJyEEENS_5ErrorERS3_RT_DpRT0_,
>
__ZNSt3__16vectorIN4llvm3orc6shared25MachOJITDylibInitializersENS_9allocatorIS4_EEE6resizeEm,
>
__ZN4llvm3orc6shared19SerializationTraitsINS1_20VectorRawByteChannelENSt3__112basic_stringIcNS4_11char_traitsIcEENS4_9allocatorIcEEEESA_vE11deserializeERNS1_14RawByteChannelERSA_,
>
__ZN4llvm3orc6shared23fromWrapperFunctionBlobIJyEEENS_5ErrorENS_8ArrayRefIhEEDpRT_,
> __ZTIN4llvm6detail23provider_format_adapterIRjEE,
> __ZN4llvm3orc6shared21WrapperFunctionResult20getAnyOutOfBandErrorEv,
> __ZTIN4llvm3orc6shared20VectorRawByteChannelE,
> ___orc_rt_macho_get_initializers_remote,
> __ZTIN4llvm3orc6shared14RawByteChannelE,
>
__ZNSt3__16vectorIhNS_9allocatorIhEEE26__swap_out_circular_bufferERNS_14__split_bufferIhRS2_EE,
>
__ZN4llvm3orc6shared19SerializationTraitsINS1_20VectorRawByteChannelENSt3__16vectorINS1_25MachOJITDylibInitializers13SectionExtentENS4_9allocatorIS7_EEEESA_vE11deserializeERS3_RSA_
> }) }
>
/Users/staefsn/Develop/LLVM/monorepo/llvm-orc-runtime/build/bin/llvm-jitlink-executor:Response
> has unknown sequence number 527162
>
> On 18/01/2021 08:55, Lang Hames wrote:
>
> Hi All,
>
> Happy 2021!
>
> I've just posted a new Orc Runtime Preview patch:
>
https://github.com/lhames/llvm-project/commit/8833a7f24693f1c7a3616438718e7927c6624894
>
> Quick background:
>
> To date, neither ORC nor MCJIT have had their own runtime libraries. This
> has limited and complicated the implementation of many features (e.g. jit
> re-entry functions, exception handling, JID'd initializers and
> de-initializers), and more-or-less prevented the implementation of others
> (e.g. native thread local storage).
>
> Late last year I started work on a prototype ORC runtime library to
> address this, and with the above commit I've finally got something
worth
> sharing.
>
> The prototype above is simultaneously limited and complex. Limited, in
> that it only tackles a small subset of the desired functionality. Complex
> in that it's one of the most involved pieces of functionality that I
> anticipate supporting, as it requires two-way communication between the
> executor and JIT processes. My aim in choosing to tackle the hard part
> first was to get a sense of our ultimate requirements for the project,
> particularly in regards to *where it should live within the LLVM Project*.
> It's not a perfect fit for LLVM proper: there will be lots of target
> specific code, including assembly, and it should be easily buildable for
> multiple targets (that sounds more like compiler-rt). On the other hand
> it's not a perfect fit for compiler-rt: it shares data structures with
> LLVM, and it would be very useful to be able to re-use llvm::Error  /
> llvm::Expected (that sounds like LLVM). At the moment I think the best way
> to square things would be to keep it in compiler-rt, allow inclusion of
> header-only code from LLVM in compiler-rt, and then make Error / Expected
> header-only (or copy / adapt them for this library). This will be a
> discussion for llvm-dev at some point in the near future.
>
> On to the actual functionality though: The prototype makes significant
> changes to the MachOPlatform class and introduces an ORC runtime library in
> compiler-rt/lib/orc. Together, these changes allow us to emulate the dlopen
> / dlsym / dlclose in the JIT executor process. We can use this to define
> what it means to run a *JIT program*, rather than just running a JIT
> function (the way TargetProcessControl::runAsMain does):
>
> ORC_RT_INTERFACE int64_t __orc_rt_macho_run_program(int argc, char *argv[])
> {
>   using MainTy = int (*)(int, char *[]);
>
>   void *H = __orc_rt_macho_jit_dlopen("Main", ORC_RT_RTLD_LAZY);
>   if (!H) {
>     __orc_rt_log_error(__orc_rt_macho_jit_dlerror());
>     return -1;
>   }
>
>   auto *Main = reinterpret_cast<MainTy>(__orc_rt_macho_jit_dlsym(H,
"main"
> ));
>   if (!Main) {
>     __orc_rt_log_error(__orc_rt_macho_jit_dlerror());
>     return -1;
>   }
>
>   int Result = Main(argc, argv);
>
>   if (__orc_rt_macho_jit_dlclose(H) == -1)
>     __orc_rt_log_error(__orc_rt_macho_jit_dlerror());
>
>   return Result;
> }
>
> The functions __orc_rt_macho_jit_dlopen, __orc_rt_macho_jit_dlsym,
> and __orc_rt_macho_jit_dlclose behave the same as their dlfcn.h
> counterparts (dlopen, dlsym, dlclose), but operate on JITDylibs rather than
> regular dylibs. This includes running static initializers and registering
> with language runtimes (e.g. ObjC).
>
> While we could run static initializers before (e.g. via
> LLJIT::runConstructors), we had to initiate this from the JIT process side,
> which has two significant drawbacks: (1) Extra RPC round trips, and (2) in
> the out-of-process case: initializers not running on the executor thread
> that requested them, since that thread will be blocked waiting for its call
> to return. Issue (1) only affects performance, but (2) can affect
> correctness if the initializers modify thread local values, or interact
> with locks or threads. Interacting with threads from initializers is
> generally best avoided, but nonetheless is done by real-world code, so we
> want to support it. By using the runtime we can improve both performance
> and correctness (or at least consistency with current behavior).
>
> The effect of this is that we can now load C++, Objective-C and Swift
> programs in the JIT and expect them to run correctly, at least for simple
> cases. This works regardless of whether the JIT'd code runs in-process
or
> out-of-process. To test all this I have integrated support for the
> prototype runtime into llvm-jitlink. You can demo output from this tool
> below for two simple input programs: One swift, one C++. All of this is
> MachO specific at the moment, but provides a template that could be easily
> re-used to support this on ELF platforms, and likely on COFF platforms too.
>
> While the discussion on where the runtime should live plays out I will
> continue adding / moving functionality to the prototype runtime. Next up
> will be eh-frame registration and resolver functions (both currently in
> OrcTargetProcess). After that I'll try to tackle support for native
MachO
> thread local storage.
>
> As always: Questions and comments are very welcome.
>
> -- Lang.
>
> lhames at Langs-MacBook-Pro scratch % cat foo.swift
> class MyClass {
>   func foo() {
>     print("foo")
>   }
> }
>
> let m = MyClass()
> m.foo();
>
> lhames at Langs-MacBook-Pro scratch % xcrun swiftc -emit-object -o foo.o
> foo.swift
> lhames at Langs-MacBook-Pro scratch % llvm-jitlink -dlopen
> /usr/lib/swift/libswiftCore.dylib foo.o
> foo
> lhames at Langs-MacBook-Pro scratch % llvm-jitlink -oop-executor -dlopen
> /usr/lib/swift/libswiftCore.dylib foo.o
> foo
> lhames at Langs-MacBook-Pro scratch % cat inits.cpp
> #include <iostream>
>
> class Foo {
> public:
>   Foo() { std::cout << "Foo::Foo()\n"; }
>   ~Foo() { std::cout << "Foo::~Foo()\n"; }
>   void foo() { std::cout << "Foo::foo()\n"; }
> };
>
> Foo F;
>
> int main(int argc, char *argv[]) {
>   F.foo();
>   return 0;
> }
> lhames at Langs-MacBook-Pro scratch % xcrun clang++ -c -o inits.o inits.cpp
> lhames at Langs-MacBook-Pro scratch % llvm-jitlink inits.o
>
> Foo::Foo()
> Foo::foo()
> Foo::~Foo()
> lhames at Langs-MacBook-Pro scratch % llvm-jitlink -oop-executor inits.o
> Foo::Foo()
> Foo::foo()
> Foo::~Foo()
>
> -- https://flowcrypt.com/pub/stefan.graenitz at gmail.com
>
>
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